Torrential downpours to pose dangerous flash flood risk in southeast US in early August
Days of downpours and flash floods will ruin outdoor plans and create dangers in parts of the southeastern United States into this week, while a wedge of cooler and less humid air over the interior will be brief.
AccuWeather flooding expert Alex Sosnowski was live on the AccuWeather Network on Aug. 5 to discuss the flash flooding risk in the southeastern U.S.
Multiple factors will combine in the southeastern corner of the United States during the first several days of August to pose a serious risk to lives and property through flash flooding.
August will continue where July left off in terms of flash flooding, as many inches of rain are forecast to pour down, especially from northern Florida and southeastern Alabama to southern Georgia and portions of South Carolina.
Rainfall rates of 1-3 inches per hour are possible during the downpours Tuesday. At this rate, storm drains can easily be overwhelmed, leading to deep water on some streets and underpasses of major highways. Washouts can occur along some rural roads where small streams are turned into raging erosive torrents.
"An area of particular concern could be southeastern Georgia and coastal South Carolina, where these downpours may be quite persistent," AccuWeather Senior Meteorologist Dan Pydynowski said.
This is the zone where downpours may repeat early this week.
"A general 4-8 inches of rain could fall over this area over the course of several days, causing street and highway flooding in low-lying areas around cities such as Savannah, Georgia," Pydynowski explained.
Over a period of five days, a broad area, where 2-4 inches of rain is forecast to fall, will extend over multiple states in the Southeast with an AccuWeather Local StormMax™ of 12 inches.
Places such as Charlotte and Greenville, South Carolina, cooled down and turned significantly less humid over the weekend as a wedge of dry air arrived from the Northeast states. Highs in Charlotte were in the mid-70s, while highs were in the low-to-mid-70s in Greenville this weekend. Meanwhile, temperatures struggled to reach 70 in Atlanta on Monday, following a high in the 70s on Sunday.
The last time the zone from Charlotte to Atlanta had consecutive days with highs in the 70s (or lower) was back in May. High humidity has been relentless in much of the Southeast.
The cooler air won't make much progress in Florida. While 100-degree temperatures that occurred in Tampa earlier this week will not be repeated, highs will be well into the 90s over central and South Florida this week.
This week, high pressure responsible for a major outbreak of cool air in the Northeast will slide off the New England coast. A southeast breeze will then usher in higher humidity levels and tropical moisture over the interior Southeast states.
This expanse or return of moisture is likely to bring downpours to parts of the Southeast and Appalachian areas in Georgia, the Carolinas and perhaps Virginia.
As the moisture rebound occurs, flash flooding may develop where downpours persist.
Watching nearby Atlantic for tropical development
The risk of flooding downpours will continue along the southern Atlantic coast to portions of the northeastern Gulf coast through the rest of the week from a stalled front and perhaps a tropical entity.
Even as Dexter moves away from the U.S., a new threat may arrive in roughly the same waters off the southern Atlantic coast. This time, steering breezes would guide any tropical depression or storm that forms onshore in the Carolinas, rather than out to sea.
AccuWeather hurricane experts are monitoring two areas for the potential for tropical development mid- to late week. Rain and wind impacts are possible for portions of the Southeast towards late week. Individuals are urged to check AccuWeather often for the latest information.
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